1. Field
Aspects of embodiments of the present invention relate to a pixel and an organic light emitting display device having the pixel.
2. Description of Related Art
Organic light emitting display devices are a type of flat panel display device using an organic compound as a light emitting material, which are thin and light and can be driven by low power, as well as having good luminance and color purity, such that they can be used in various display devices, including portable display devices.
Such organic light emitting display devices have a plurality of pixels including an organic light emitting diode, which is an element that self-emits light. Further, in active organic light emitting display devices, each pixel is provided with a plurality of transistors and capacitors to drive the organic light emitting diode.
Here, a storage capacitor that stores data signals and a boosting capacitor that performs a boosting operation in accordance with changes in voltage of a signal line to display more accurate gradation are utilized in each pixel. The luminance of each pixel provided with the storage capacitor and the boosting capacitor depends on the capacitance ratio of these two capacitors.
Therefore, the capacitance ratio of the storage capacitor and the boosting capacitor should be kept uniform in all of the pixels to implement uniform luminance.
However, the boosting capacitor is generally designed to be smaller in capacity (or capacitance) than the storage capacitor, such that changes in accordance with process variations increase relatively (or are more significant for the smaller boosting capacitor). In this case, a luminance difference may occur due to differences in capacitance, between the boosting capacitors in the different pixels.